Surface termination during GaN growth by metalorganic vapor phase epitaxy determined by ellipsometry
journal contributionposted on 01.01.2003, 00:00 by C. Cobet, T. Schmidtling, M. Drago, N. Wollschlager, N. Esser, W. Richter, Randall FeenstraRandall Feenstra, T. U. Kampen
Spectroscopic ellipsometry is used to study GaN films during growth by metalorganic vapor phase epitaxy (MOVPE) in correlation to well known results of plasma-assisted molecular beam epitaxy (PAMBE). Results for the PAMBE reveal clear differences between growth under Ga-rich and N-rich conditions, which are attributed to the presence of a Ga bilayer on the surface (also seen with low energy electron diffraction) in the Ga-rich case. Results for MOVPE surfaces during growth or for surfaces which are stabilized under NH3 are very similar to the N-rich PAMBE result. It is concluded that under normal growth conditions in MOVPE in contrast to PAMBE the surface is not terminated by a Ga bilayer. © 2003 American Institute of Physics.